One-part silicone compositions of the condensation cure type are used as sealing agents, adhesives, coating agents or potting agents in a wide variety of areas including buildings, electric and electronic equipment and components, transporting vehicles, electric appliances and the like. Since air-borne moisture is necessary for crosslinking reaction to take place, rubber gradually forms from the surface. This suggests that it takes several days until the composition cures to depth. It is thus very difficult to acquire an adhesion strength immediately after application. Green strength can be increased by heavily loading a silicone composition with fumed silica to provide an extremely increased viscosity. This improvement is made at the sacrifice of working efficiency.
Also used as sealing agents, adhesives, coating agents or potting agents are two-part silicone compositions of the condensation cure type in which a crosslinking agent is provided as a separate package. As compared with the one-part compositions, the two-part compositions are improved in deep cure. JP-A 7-118531 discloses that the combined use of an amine compound and a ketone compound enhances the deep cure. This composition still requires several days until satisfactory bond strength is developed.
One known measure of providing initial adhesion is JP-B 7-119395 that discloses a composition comprising a siloxane polymer composed of R3SiO1/2 units and SiO4/2 units, an organopolysiloxane having hydrolyzable silyl groups bonded at opposite ends via siloxane linkages, and a condensation catalyst. It is still desired to improve the bond strength development of this composition.